Method, apparatus, and tools for precision polishing of lenses and lens molds

Abstract

A tool, apparatus, and method for polishing objects having a wide variety of materials and shapes including precision optical surfaces, injection mold inserts, and thin film coating dies; and in particular, objects having deeply concave precision surfaces. The tool has a rotatably drive wheel engaged with a polishing wheel by use of a polishing foil formed as a flexible belt. The polishing wheel may have a cavity within, such cavity being inflatable using a variety of fluids having a range of physical properties. The polishing wheel is adjustably positionable against an object to be polished by actuating means joined thereto. The apparatus comprises a multi-axis computer controlled machine to which the tool is attached.

We claim:  
     
         1 . A polishing tool comprising 
 a) a base for affixing objects thereto;    b) a drive wheel joined to a rotatable shaft, said drive wheel having a perimeter, and said rotatable shaft disposed in a housing joined to said base;    c) a rotatable polishing wheel having a perimeter;    d) a polishing foil engagable with a portion of said perimeter of said drive wheel and engagable with a portion of said perimeter of said polishing wheel, and.    e) a first actuating means for engaging said polishing foil with said portion of said perimeter of said drive wheel and with said portion of said perimeter of said polishing wheel.    
     
     
         2 . The polishing tool as recited in  claim 1 , wherein said first actuating means comprises a first linear actuator operatively attached to said polishing wheel.  
     
     
         3 . The polishing tool as recited in  claim 2 , wherein said first linear actuator is a pressure-driven cylinder.  
     
     
         4 . The polishing tool as recited in  claim 3 , wherein said pressure driven cylinder is an air operated cylinder.  
     
     
         5 . The polishing tool as recited in  claim 3 , wherein said pressure driven cylinder is a hydraulically operated cylinder.  
     
     
         6 . The polishing tool as recited in  claim 2 , wherein said polishing foil comprises a belt.  
     
     
         7 . The polishing tool as recited in  claim 6 , wherein said belt is an elastic belt.  
     
     
         8 . The polishing tool as recited in  claim 7 , wherein said foil of further comprises an abrasive ring.  
     
     
         9 . The polishing tool as recited in  claim 6 , wherein said foil is impregnated with abrasive particles selected from the group consisting of ceria, alumina, silica, diamond, and mixtures thereof.  
     
     
         10 . The polishing tool as recited in  claim 6 , wherein said belt is a flat belt.  
     
     
         11 . The polishing tool as recited in  claim 6 , wherein said belt is a toothed belt.  
     
     
         12 . The polishing tool as recited in  claim 2 , wherein said polishing foil is between about 0.25 and about 5 inches wide.  
     
     
         13 . The polishing tool as recited in  claim 2 , further comprising a second actuating means for positioning said polishing wheel and said polishing foil.  
     
     
         14 . The polishing tool as recited in  claim 13 , wherein said second actuating means comprises a second linear actuator.  
     
     
         15 . The polishing tool as recited in  claim 14 , wherein said second linear actuator is a pressure-driven cylinder.  
     
     
         16 . The polishing tool as recited in  claim 15 , wherein said pressure driven cylinder is an air operated cylinder.  
     
     
         17 . The polishing tool as recited in  claim 15 , wherein said pressure driven cylinder is a hydraulically operated cylinder.  
     
     
         18 . The polishing tool as recited in  claim 14 , wherein said second linear actuator moves said polishing wheel along an arcuate path.  
     
     
         19 . The polishing tool as recited in  claim 1 , wherein said polishing wheel has an exterior portion consisting essentially of an elastomer.  
     
     
         20 . The polishing tool as recited in  claim 19 , wherein said elastomer is of a durometer of between about 10 and about 90.  
     
     
         21 . The polishing tool as recited in  claim 1 , wherein said polishing wheel has a cavity formed within the interior thereof.  
     
     
         22 . The polishing tool as recited in  claim 21 , wherein said polishing wheel further comprises a passageway into said cavity.  
     
     
         23 . The polishing tool as recited in  claim 22 , wherein said passageway has an inflation device disposed therein.  
     
     
         24 . The polishing tool as recited in  claim 21 , wherein said cavity contains a liquid.  
     
     
         25 . The polishing tool as recited in  claim 21 , wherein said cavity contains a gas.  
     
     
         26 . The polishing tool as recited in  claim 1 , wherein at least a portion of said polishing wheel has a spherical surface.  
     
     
         27 . The polishing tool as recited in  claim 1 , wherein said housing joined to said base has at least one bearing engaged with said rotatable shaft.  
     
     
         28 . The polishing tool as recited in  claim 1 , wherein said base comprises a substantially flat plate of rigid material.  
     
     
         29 . The polishing tool as recited in  claim 1 , further comprising a dowel pin disposed in said base.  
     
     
         30 . The polishing tool as recited in  claim 1 , wherein said drive wheel and said polishing wheel are between about 0.25 and about 8 inches in diameter.  
     
     
         31 . A polishing tool comprising 
 a) a base for affixing objects thereto;    b) a drive wheel joined to a rotatable shaft, said drive wheel having a perimeter, and said rotatable shaft disposed in a housing joined to said base;    c) a rotatable polishing wheel having a perimeter;    d) a polishing foil engaged with a portion of said perimeter of said drive wheel and engaged with a portion of said perimeter of said polishing wheel, and    e) a first actuating means for for positioning said polishing wheel and said polishing foil.    
     
     
         32 . The polishing tool as recited in  claim 31 , wherein said first actuating means comprises a first linear actuator operatively attached to said polishing wheel.  
     
     
         33 . The polishing tool as recited in  claim 32 , wherein said first linear actuator is a pressure-driven cylinder.  
     
     
         34 . The polishing tool as recited in  claim 32 , wherein said first linear actuator moves said polishing wheel along an arcuate path.  
     
     
         35 . An apparatus for polishing objects comprising: 
 a) a first linear slide movable along a first axis, disposed upon a base;    b) a first rotatable spindle engaged with said first linear slide, said first rotatable spindle further comprising a first chuck, and said first rotatable spindle aligned with said first axis;    c) a second linear slide movable along a second axis, engaged with said first linear slide, with said second axis disposed orthogonally to said first axis;    d) a second rotatable spindle engaged with said second linear slide, said second rotatable spindle further comprising a second chuck; and    e) a polishing tool engaged with said second chuck of said second rotatable spindle, said polishing tool comprising a base for affixing objects thereto; a drive wheel joined to a rotatable shaft, said drive wheel having a perimeter, and said rotatable shaft disposed in a housing joined to said base; a rotatable polishing wheel having a perimeter; a polishing foil engagable with a portion of said perimeter of said drive wheel and engagable with a portion of said perimeter of said polishing wheel, said polishing foil rotatably coupling said drive wheel with said polishing wheel; and a first actuating means for engaging said polishing foil with said portion of said perimeter of said drive wheel and with said portion of said perimeter of said polishing wheel.    
     
     
         36 . The apparatus as recited in  claim 35 , wherein said actuating means is a first linear actuator.  
     
     
         37 . The apparatus as recited in  claim 36 , wherein said first linear actuator is a pressure-driven cylinder.  
     
     
         38 . The apparatus as recited in  claim 35 , further comprising a second actuating means for positioning said polishing wheel and said polishing foil.  
     
     
         39 . The apparatus as recited in  claim 38 , wherein said second actuating means is a second linear actuator.  
     
     
         40 . The apparatus as recited in  claim 39 , wherein said second linear actuator is a pressure-driven cylinder.  
     
     
         41 . The apparatus as recited in  claim 35 , further comprising a third linear slide movable along a third axis, engaged with said first linear slide, and engaged with said second linear slide, with said third axis disposed orthogonally to said first axis and said second axis.  
     
     
         42 . The apparatus as recited in  claim 41 , further comprising a computer in control of said first linear slide, said second linear slide, said third linear slide, said first rotatable spindle, and said second rotatable spindle.  
     
     
         43 . The apparatus as recited in  claim 35  further comprising a fluid delivery system comprised of a reservoir, a pump, and a fluid conduit directed at said foil of said polishing tool.  
     
     
         44 . A method of polishing a surface of an object using a machine tool apparatus comprising a polishing tool comprised of a base for affixing objects thereto; a drive wheel joined to a rotatable shaft, said drive wheel having a perimeter, and said rotatable shaft disposed in a housing joined to said base; a rotatable polishing wheel having a perimeter; a polishing foil engagable with a portion of said perimeter of said drive wheel and engagable with a portion of said perimeter of said polishing wheel, said polishing foil rotatably coupling said drive wheel with said polishing wheel; and a first actuating means for engaging said polishing foil with said portion of said perimeter of said drive wheel and with said portion of said perimeter of said polishing wheel; said method comprising the steps of: 
 a) preparing said polishing tool for said polishing of objects;    b) preparing and programming said machine tool for said polishing of objects;    c) executing a first polishing cycle with said machine tool apparatus, wherein said polishing tool is in contact with said surface of said object; and    d) measuring said surface of said object.